This invention relates to a punching press including exchangeable tool sets having upper and lower punching tools wherein the parts punched out by the punching dies of the tools are discharged through a stacking duct in the lower punching tool. The punching press of the present invention may advantageously be utilized for punching out sheet-metal parts for electrical machinery and the like.
A substantial disadvantage of previously contemplated punching presses of this type is that an exchanging of the punching tools (blanking dies) is very cumbersome and time-consuming due to the fact that basket- or cage-type stacking ducts through which the cut-out metal sheets were discharged from the area underneath the punching tool were extended through an underlying press table or workholding plate and were attached in the zone of the underside of the tool. Consequently these stacking ducts had to be detached and lowered before each exchange of punching tools or dies. Prior arrangements also required removal of a portion of the metal sheets present in the ducts from the tool zone before the tool could be removed or disassembled.
The present invention contemplates providing punching apparatus which avoids the above-mentioned disadvantages by configuring and constructing the stacking ducts so that they need not be detached and removed or emptied during exchange of punching tool sets.
An important feature of the present invention is the spacing of the stacking duct structure from a conveying system for removal of the punched out parts from the stacking ducts and the spacing of the stacking duct structure from the press table surface of the press which supports a toolholding plate and the lower punching tool. In a preferred embodiment of the invention, the conveying system includes magnetic conveyor belts extending in grooves formed in the press table and extending from adjacent the bottom of the stacking ducts to remote part storage locations.
With the arrangement of the present invention, the entire toolholding plate with stacking inserts forming the stacking ducts located therein, including the punched out parts collected in the stacking ducts and the lower punching tool, can be moved as a unit laterally out of the press. For moving this unit out of the press, hydraulically liftable rollers or mechanical displacing means including a rope, a chain, or a rack-and-pinion gear, or similar devices can be utilized according to the present invention. However, a particularly preferred embodiment of the present invention uses air cushion means for vertically supporting the unit as it is moved laterally along the press table and bracket means connected thereto.
In preferred embodiments, the units, including toolholding plates, punching tools, and stacking inserts, are pushed out of the press at the front or at the rear thereof on fixed or movable supporting brackets and, at that point (located remotely laterally of the press ram travel path and press table), can rapidly be exchanged for a new punching tool or set of punching tools with the aid of a lifting means.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.